2种不同生活型杉叶藻的光合特性
Photosynthetic Characteristics in Two Different Life Forms of Hippuris vulgaris

利用Junior-PAM调制叶绿素荧光仪测定九寨沟箭竹海沉水和挺水杉叶藻(Hippuris vulgaris)的快速光响应曲线、最大光化学效率(Fv/Fm)、光化学淬灭(qp)和非光化学淬灭(NPQ)的日动态，探讨不同生活型杉叶藻的光合特性对九寨沟高原湖泊环境适应的特性和机制。结果表明，沉水杉叶藻的最大相对电子传递速率(rETRmax)和半饱和光强(Ek)的日变化均呈双峰型曲线，而挺水杉叶藻rETRmax和Ek日变化呈单峰曲线；沉水和挺水杉叶藻光能利用效率均呈早晚高、中午低的近“V”型曲线。挺水杉叶藻的rETRmax、Ek、qp和NPQ日平均值极显著高于沉水杉叶藻，挺水杉叶藻通过增加光耗散尽量降低光抑制程度，具有更高光合能力和对强光的耐受能力。以上结果说明：不同生活型杉叶藻的叶绿素荧光参数有一定差异，挺水杉叶藻对强光的适应能力强于沉水杉叶藻。
Submerged and emerged Hippuris vulgaris were selected in Jiuzhaigou to examine diurnal variations of rapid light curves (RLCs), maximal quantum yield (Fv/Fm), photochemical quenching (qp) and non-photochemical quenching (NPQ) using pulse-amplitude modulated fluorometer (Junior-PAM) in Jianzhu Lake.The purpose is to investigate the photosynthetic characteristics of different life forms of H.vulgaris and adaptive strategies against environmental in alpine lakes. The results showed that the diurnal variations of submerged H.vulgaris of maximum relative electron transport rate (rETRmax) and saturating photon flux (Ek) presented a typical bimodal curve, while those of emerged H.vulgaris presented unimodal curve. The photosynthetic efficiency (α) of submerged and emerged H.vulgaris was V pattern diurnal cycle, α was the highest at sunrise and sunset, α was the lowest at noon. The daily averages of rETRmax, Ek, qp and NPQ of emerged H.vulgaris were significantly greater than that of submerged H.vulgaris.Therefore it dissipated excess light energy depending on the increase of NPQ, emerged H.vulgaris was a plant with a strong photosynthetic capacity for acclimation to high light intensity. The results indicated that significant differences in chlorophyll fluorescence parameters were found between submerged and emerged H.vulgaris, emerged H.vulgaris was more tolerant to strong light intensity than submerged H.vulgaris.